Hydrocarbon (HC) vapor traps are used in internal combustion engines to capture hydrocarbon vapors which may emanate from the interior of the engine and would otherwise leak into the environment. HC traps therefore are part of a vehicle's pollution control system, reducing potentially harmful evaporative emissions from the engine.
U.S. patent application Ser. No. 13/657,544 filed on Oct. 22, 2012, by the owner of this Application (the disclosure of which is incorporated herein by reference) discloses a HC vapor trap including one or more layers or sheets of a polymeric material impregnated with a HC vapor adsorption/desorption material. The layer or layers of the polymeric material may be formed to a desired shape by heat and/or pressure in a process referred to as thermoforming. The use of thermoformed polymeric material sheets provides structural integrity to the HC trap while retaining the adsorption/desorption functionality via the impregnated HC vapor adsorption/desorption material. The improved structural integrity allows a vapor trap assembly to be constructed with a reduced need for additional components to retain the trap material in its operative position